1. Field of the Invention
The present invention relates to a rotational sliding switch employed, for example, for an inhibitor switch for detecting a shift position in an automatic transmission.
2. Description of the Related Art
An inhibitor switch such as shown in FIGS. 10 and 11 is a conventional rotational sliding switch. FIG. 10 is an exploded perspective view of the conventional inhibitor switch and FIG. 11 shows another conventional inhibitor switch, wherein (a) is a cross-sectional view thereof and (b) is a cross sectional view of the disassembled inhibitor switch.
In an inhibitor switch 101 shown in FIG. 10, a contact plate 117 is fixedly supported in a housing 115, and a plurality of fixed contacts 119 are provided at the contact plate 117. Further, movable contacts 123, 124 are mounted on a movable base 121. A joining hole 125 for joining to a manual shaft of an automatic transmission is provided in the movable base 121.
The housing 115 is mounted on a mission case side of the automatic transmission, and joining hole 125 of the movable base 121 is joined to the manual shaft side.
Therefore, if the manual shaft is rotated, the movable base 121 moves rotationally, the movable contacts 123, 124 are caused to slide under the prescribed contact pressure against the fixed contacts 119 and the rotation position of the manual shaft can be detected and the shift position of the automatic transmission can be detected by the sliding position of the movable contacts 123, 124 with respect to the fixed contacts 119 (for example, see Japanese Patent Application Laid-open No. H8-293228, page 4, FIG. 3).
An inhibitor switch 101A shown in FIG. 11 comprises a pole base 103 and a movable base 105. The pole base 103 is composed of a pair of sections 103a, 103b, and the sections 103a, 103b together constitute the pole base 103. A plurality of fixed contacts 107 are provided at section 103a, and a plurality of fixed constants 109 are provided at the other section 103b. 
Contact bodies 111a, 111b and a contact body 111c comprising respective movable contacts on both side surfaces thereof are provided at the movable base 105. A joining hole 113 for joining to the manual shaft of the automatic transmission is provided in the movable base 105.
Further, the above-mentioned sections 103a, 103b are mated with one another so as to sandwich the movable base 105, and the sections 103a, 103b are joined to each other, for example, by ultrasonic welding. Furthermore, the pole base 103 is fixedly supported on the mission case side of the automatic transmission, and a joining hole 113 of the movable base 105 is joined to the manual shaft.
Therefore, as the manual shaft rotates, the movable base 105 moves rotationally, the movable contacts of the contact bodies 111a, 111b and the contact body 111c slide under the prescribed contact pressure against the fixed contacts 107109 and the rotation position of manual shaft can be detected and the shift position of the automatic transmission can be detected by the sliding position of the movable contacts against the fixed contacts 107109 (for example, see Japanese Patent No. 2705730, pages 3, 4, FIGS. 1, 4).
The problem associated with the structure described in Japanese Patent Application Laid-open No. H8-293228 is that because a plurality of the fixed contacts 119 are supported on one side surface of the contact plate 117, when the number of the fixed contacts 119 is increased as required, the contact plate 117 unavoidably increases in size accordingly and the structure is enlarged.
By contrast, in the structure described in Japanese Patent No. 2705730, the pole base 103 is composed of a pair of sections 103a, 103b, and the fixed contacts 107109 are provided on respective sections. As a result, the increase in size of the entire structure can be controlled even when the number of the fixed contacts 107109 is increased as required.
However, the problem is that because the pole base 103 is composed of a pair of the sections 103a, 103b and those sections are joined to each other, for example, by ultrasonic welding, a manufacturing error such as inaccurate mutual alignment of the fixed contacts 107109 can easily occur. Furthermore, the fixed contacts 107109 have to be insert molded individually on each of the pair of sections 103a, 103b, this process being cost inefficient.
It is an object of the present invention to provide a rotational sliding switch which can be manufactured with high accuracy and at a low cost and in which the increase in size can be controlled even when the number of fixed contact points is increased.